1. Field of the Invention
The present invention is broadly concerned with improved impact absorbing shoes having a section of artificial turf as a part of the soles thereof. More particularly, the invention is concerned with such improved shoes, and midsoles used in the construction of composite shoe soles, wherein artificial turf is embedded within the composite soles of the shoes.
2. Description of the Prior Art
The human foot has 26 bones, 33 joints, 19 muscles, and a number of interconnecting ligaments. These components normally work together in perfect precision and the person is generally unaware of any of these parts. A human foot may strike the ground 10,000 times a day and cover more than 115,000 miles in a lifetime. An average athlete will generate up to 700 lbs of pressure on a foot in a single leap or stride.
There are three energy-storing mechanisms in a human foot. As the Achilles tendon stretches when a person steps down, the tendon stores energy. The release of this energy occurs when the person steps off and the tendon relaxes. The arch of the human foot flattens when a step is taken, thus storing energy, and the arch releases its stored energy when a step is taken. The third mechanism is a cushion under the heel of the foot which acts as a shock absorber and stores energy as it is compressed.
In light of the complexity of the human foot, and the pain which can accompany any foot injuries, considerable research has been done in the past in an effort to provide comfortable, impact absorbing shoes. This is particularly the case for various types of athletic shoes, such as tennis, walking, or running shoes. The modern athletic shoe did not come into existence until the 1970s. Prior to that, consumers wore “sneakers,” or rubber-soled shoes with canvas tops. However, beginning in the late 1960s, Nike, Inc. and The New Balance Shoe Company were formed for the purpose of developing improved running shoes. These companies, and many subsequent competitors, developed a bewildering number of athletic shoe types, which we see today. Notwithstanding all of these efforts, there is a continuing search for improved shoes in terms of comfort, support, and overall wearing experience.
Artificial turfs were originally created in the mid-1960s and have also seen a long history of development. The first major commercial product “AstroTurf” was installed in the Houston Astrodome in 1966. Since that time, many improvements have been made, and the patent art is replete with references describing various types and modifications of artificial turfs, see, e.g., U.S. Pat. No. 7,357,966 and Publication No. 2011/0081506. Generally speaking, present-day artificial turfs include a woven backing sheet with a plurality of artificial grass blades sewn into the sheet. These blades are typically formed using polyethylene or similar synthetic resin materials. Additionally, these turfs are provided with an infill between the blades, which include elastomeric rubber particles or crumbs. These artificial turfs closely mimic the characteristics of high-grade natural turfs, but have lower maintenance costs and longer lives.